Parallel keys high form, round-headed without bore DIN 6885A-steel C45K+C 4x4x25

Steel is an iron-carbon alloy with a maximum carbon content of 2% by mass. The steels achieve their intended physical and mechanical properties through various hardening, annealing and tempering processes. It is also possible to harden the edge zone by surface hardening, case hardening or nitriding. Well-known steel grades are structural steels, free-machining steels, case-hardening steels, nitriding steels, tempering steels, tool steels and stainless steels.

The term plain indicates a completely untreated, merely oiled, smooth surface for all DIN and ISO screws such as wood screws, hexagon head screws, threaded rods, nuts and many types of washers.

The 1.0503 / C45 is an unalloyed tempered steel. This structural steel can be used in a variety of ways, although the mechanical properties depend very much on the heat treatment (annealing, tempering). C45 is well suited for components with low stress, e.g. machine parts, axles, bolts or possibly knives. The C45 can only be welded to a limited extent.